The inventor of the light bulb, when you get right down to it, can shoulder the blame for some potentially frightening health possibilities facing 11 million workers.

They’re those who work the graveyard shift. Research is showing that these creatures of the night – nurses, bakers, firefighters, transportation workers, factory employees, police officers, 24-hour help-deskers and others – might encounter several serious risks:

• International researchers, analyzing results of 34 studies, found that shift work was associated with a 23 percent increased risk of heart attack among more than 2 million night, evening and rotating-shift workers, the British Medical Journal reported. Among night-shift workers only, that number rose to 41 percent. Interestingly, shift work was not associated with increased death rates.

• Researchers at Brigham & Women’s Hospital Division of Sleep Medicine found that among workers with pre-diabetes conditions, the disease is more likely to develop in night workers than those who work days. Additionally, sleeping at “abnormal times” and not getting enough sleep leads to lower metabolism and higher spikes in blood sugar.

• Teens who work “off-hour employment” before age 20 may be at risk for multiple sclerosis due to changes in their sleep patterns and disruption of their circadian rhythms, according to the Karolinska Institutet in Stockholm.

So perhaps the maligning of Edison – “the person to blame, obviously,” says Dr. David Luterman, medical director of the Baylor Sleep Center in Dallas – now makes more sense.

“When it was dark, there was nothing to do but sleep,” Luterman says. “Then the light bulb came, and then Henry Ford puts in shifts all over the place. Then radio, which was entertainment in your own home. Then the TV.”

Which led, of course, to overnight jobs, to off-kilter sleep schedules and to health problems that go bump in the night.

First though, a caveat: While these shifts can lead to serious health issues, they’re not a given.

“It can mess up your life,” Luterman acknowledges. “But not everybody who does shift work is affected. About 20 percent have significant problems doing it. There’s no rhyme or reason who will or won’t.”

Every cell in our bodies, he says, has a biological rhythm. The brain has a master clock that trains us to be awake during the day and asleep at night. Thus, when light and dark are out of whack, so are we – if we’re not careful.

“Simply put, the human body is designed and wired to respond to diurnal cues that have to do with nature’s clock: daylight and nighttime,” says Gerry Jacob. He’s CEO of Wellfirst Sleep Diagnostics, whose sleep centers throughout North Texas evaluate and treat people with sleep issues.

Upending that by working at night or by alternating sleep and wake shifts can lead to dysfunction, Jacob says. For instance, it throws off production of melatonin – the hormone responsible for rest.

As far as causing obesity and other problems, Luterman says he is unsure of the correlation. There is one, he says, “but I don’t know the physiology of it.

“Hormones, insulin, things like that are secreted in diurnal variation,” Luterman says. “When you do shift work, you’re opposing some of your normal hormone stasis equilibrium.”

One problem is that people get their nights and days mixed up, he says.

“They work at night, but try to revert back to daytime on their days off. If you try to reverse, you’ll have a hard time doing it. You have to shift your sleep schedule.”

Kevin Campbell, an overnight emergency-room charge nurse at Texas Health Presbyterian Hospital of Dallas, stresses such advice with nurses new to the shift.

“People who try to be with their families heavy-duty on their days off and twist things around have a harder time,” Campbell says. He’s worked (and loved working) nights full time since he became a nurse in 1997, and two years before that as a patient-care technician.

The 7 p.m. to 7 a.m. shift, which Campbell does three times a week, complements his internal rhythm, he says. “I’ve always been a night person. I never have a hard time staying awake.”

That’s not true of everyone who works nights.

Significant sleep problems for night workers, Luterman says, typically fall into two categories: not being able to stay awake at work or not being able to sleep during the day.

Snoozing on the job can lead to no longer having the job, or, worse, putting lives in danger.

A lot of her staff has a hard time getting used to sleeping during the day, says Tarah Grooms, director of the emergency department at Methodist Richardson Medical Center. “But then they get on a cycle and do it. A lot here have done it for 20 years. That’s their life.”

The pay is also better, she says.

Tips for late-shift workers

• Regulate light and dark. When night-shifters get off work, the sunlight while they’re driving home stimulates them to stay awake, says Dr. David Luterman. “We tell people, ‘Wear dark sunglasses on your way home. Use blackout curtains so when you go into your house, it’s dark.’ ”

Adds Tarah Grooms of Methodist Richardson Medical Center: “Some use earplugs or soft music. There’s an app for the sound of rain. A lot of nurses use that.”

• Sleep when you can; just be sure to sleep. For some people, it may be right after they get off work. Others might want to wind down first.

“Remember you still have the same amount of time between shifts, days and nights,” Grooms says.

• Use rotating shifts to your advantage. If you have a choice, Luterman says, opt for a day-evening-night shift rotation over night-evening-day. “It’s easier to advance it than to reduce it, just like it’s easier to fly and adapt from Los Angeles to New York than New York back to L.A.”

• Make sure your work area is well-lighted. “The lights are always on here,” Grooms says.

• Regulate caffeine and stay hydrated. To make sure you can sleep when you get off work, Grooms recommends no caffeine past midnight. “Drink lots of water.” And yes, that evergreen advice: “Exercise.”